Electrical circuit breaker



May 11, 1937. 0. MASENG 2,080,178

ELECTRICAL C IRCUT BREAKER Filed Oct. 22, 1954 33 gmvmmwwmw w EL.

INVENTOR,

ATTORNEY.

Patented May ll, 1937 UNITED sTATEs k2,080,178 ELECTRICAL CIRCUIT BREAKER l l Olav Maseng, Evanston, Ill. Application October 22,` 1934, Serial No. '149,330`

20 Claims.

This invention relates to electrical circuit breakers, and an object thereof is to provide an improved means for opening an electric circuit while current is ilowing therein and including means for reducing the arcing at the terminals.

AA further object of the invention is to provide a circuit breaker of such construction that the gases produced by the arc upon initiating the opening of the circuit are utilized in a manner to provide a high pressure blast across the co-acting surfaces of the terminals.

A further and major feature of the invention resides in the provision of an intermediate contact element positioned between the main contact r of the circuit to be interrupted wherein, by first separating a main contact and the intermediate contact, an arc is drawn and thereafter the intermediate contact is separated from the other main contact permitting the gases produced by the first arc to flow under pressure between the said intermediate and second main contacts.

A still further and major object of the invention is to provide a circuit breaker including the main opposed contacts and an intermediate contact positioned therebetween in the arc path and including an auxiliary means for imposing a potential upon the intermediate contact for changing the state of ionization in the arc space and reduce the magnitude of the current flowing across the gap in the ilnal separation of the intermediate contnct and a main contact as hereinafter described thereby reducing and limiting the duty that the circuit may impose upon the cir-y cuit breaker.

It has heretofore been usual to immerse the contact structures of a high voltage circuit breaker in an insulating uid in which the high dielectric strength thereof is depended upon as a means of interruption of a circuit. Such prior circuit breakers are costly, being of comparatively large size, and further introduce a serious iire and explosion hazard. In my invention, insulating fluids are dispensed with and the arc gases of low dielectric strength, either separately or in combination with an auxiliary potential, are depended upon to reduce the arcing and are utilized for the purpose of interrupting the circuit.

These and other objects and several novel features of the invention are hereinafter more fully described and claimed, and the preferred form of construction of an electrical circuit breaker embodying my invention is shown in the accompanying drawing in which- Fig. 1 is a. longitudinal section of a convenientv form of circuit breaker embodying my invention.

(Cl. F75-294) Fig. 2 is a partial sectional view showing the contact elements in partly open position.

Fig. 3 is a similar view showing the contacts in the fully open position.

Fig. 4 is a similar view showing an alternative form of an intermediate contact element and its relationship with the main contact or electrode in which it is mounted. l

Fig. 5 is a diagrammatic view showing the contact element in the fully open position and the circuit associated therewith for producing a potential at the intermediate contact.

The fundamental form of my improved circuit breaker is shown in Fig. 1. This comprises a body of insulating material Il but the general form of this member may be varied to suit various characters of installation. This insulating member has a bore Ii which opens through one end of the insulating member and this is closed by the threaded plug 2li and any desired character of packing means 2li', preferably cementitious, may be used between the plug and the body to seal the bore Ii' at one end. In the bore is the hollow movable electrode or contact member i2 which is attached at one end in any convenient manner to the operating rod I3 which may be moved longitudinally of the axis of the contact I2 by any approved means (not here shown). The contact i2 has an external shoulder i2' that limits the withdrawal movement of the contact element as will -be understood from Fig. 3, the shoulder, upon full withdrawal, engaging the packing 20' or base of the plug 2li if the aperture of the packing element through which the electrode extends is of the same diameter as the chamber ii.

i6 which has a tapered base I0 against',which the correspondingly tapered edge at the" en'd of.

the element of the contact i2 engages in theposition shown in Fig. 1. To this intermediate contact is secured an insulating body il and the outer free end of the insulation element is formed with a collar 2i somewhat greater in diameter. 'I'his collar 2i is engaged by the internal shoulder Il when the contact i2 is withdrawn to the position shown in Fig. 2.

'Ihe intermediate electrode Il has a. cone like terminal portion 32 and as shown in Fig. 1, this coned end 32 engages the cone shaped end 33 of the hollow contact il. This contact element is mounted in a recess 34 in axial alignment with the chamber Il' and having a side outlet to atmosphere indicated at 35. The electrode or contact element Il has an extension I9 with which Within this contact element iZfis, the base of the intermediate contact or electrodev PATENT oFI-icE one side 36 of the main circuit is'connected while the other side 31 of the main circuit is connected to the contact I2 as diagrammatically shown in Fig. 1. There is a spring IS engaging a base of the main contact Il holding the same in the position shown, there being a slight movement of the contact Il on the axis of the intermediate member and the other main contact i2 to insure contact.

In this fundamental form of the invention, it will therefore be realized that there is a main contact I2, a companion main contact I4 and an intermediate contact Ii in engagement with both the said main contacts when in the closed position shown in Fig. 1. 'I'he intermediate contact II is pressed to engagement with the contact I I by means of a spring Il in the hollow contact I2. Upon starting to open the circuit in this primary construction, the contact I2 is withdrawn by means of the operating rod I3 and associated instrumentalities (not here shown) for causing said movement.

Upon initiating movement of the contact I2 the tapered edge thereof is separated from the coned face of the intermediate contact I6 which is in engagement with the main contact Il. This causes an arc and development of a high pressure gas in the chamber I I which, during this initial operation, remains closed. On

further movement of the member I2 the shoulder 3i engages the enlarged portion 2I on the insulating member withdrawing the coned face 32 out of contact with the coned mouth 33 of the hollow contact I4. This permits the high pressure gas caused by the initial separation of the contacts I2 and Ii to pass through the narrow opening between the portion I2 of the intermediate contact I6 and the coned mouth 33 of the main electrode I4 to atmosphere through the passageways 34 and 35. The gas being partially deionized and cleaned by being forced against the wall of the bore or chamber II' and narrow passage between the intermediate contact Ii and said wall. These gases are so guided as to pass over the surfaces of the intermediate electrode I6 and the main electrode I4 in intimate contact therewith and tend to quench the incipient arc between these members and maintain a steady high pressure blast over the arc terminals until the circuit is completely interrupted. To insure separation of the contacts I6 and I4, the enlarged end portion is provided for engagement with the shoulder 3| of the contact I2 whereby, prior to completion of movement of the operating rod in separating the contacts, the intermediate electrode or contact I6 is forcibly separated from the contact I 4. In fact the intermediate contact may be provided with a longer insulation as indicated at I1 in Fig. 4 so that at the limit of withdrawal movement of the contact I2 the enlarged portion 2I may then be just engaged by the shoulder 3i of the said contact I2.

In the structure shown in Fig. 4, the final separation of the intermediate contacts I6 and I4 is produced by the pressure within the chamber I I.. In this latter case, as the pressure in the chamber decreases, the intermediate contact I6 may again assume the position shown in Fig. 4 without closing the circuit as the said electrode is supported in the main electrode I2 by the insulation rod or element I'I.

In the form or forms of the invention so far described, the interruption of the arc is solely by the quenching effect of the gases developed in the chamber II' and it will be evident from the description above given, that various objects of the invention are attained by a structure that is of simple character and comparatively compact in form and without the use oi insulating iiuids heretofore commonly used in this art where high voltage circuits carrying current of high amperage are to be broken or interrupted.

The utility of the device as heretofore described, particularly for circuits carrying large currents may be enhanced as indicated in Fig. 5 which, in association with the parts heretofore described, includes an additive feature comprising an auxiliary circuit energized by the main circuit in such manner that a potential or impulse is impressed upon the intermediate electrode Il subsequent to the separation of the contact members when the circuit is being interrupted. 'I'his potential will cause the main current to be diverted to the secondary circuit in which, due to the impedance included, the current iiow will be limited to a low value which may be readily interrupted by the remaining gap between the intermediate electrode I8 and the main electrode I4.

It is therefore a function oi' the auxiliary circuit 22', 2l, 2l, II, 31, 22 to constitute an auxiliary circuit useful in impressing a positive potential on the auxiliary contact It.

The auxiliary circuit includes a current transformer 22 having its primary winding in the main circuit 21. Ihe secondary winding of the transformer also has one end connected to the main circuit at 40 while the other end is connected to the impedance 2l and lead 24 extending through the breaker structure to the intermediate contact member Ii. When the circuit breaker shown is opened by withdrawal of the electrode I2, the initial arc will be produced as heretofore described and as the intermediate electrode is being withdrawn toward the position shown in Fig. 3. current will be forced to flow in the circuit from terminal I0, contact member I4 through the arc existing between contact members I4 and Il, the line 24, impedance 23 an'i the secondary of the current transformer 22 to the main circuit l1 which, under this condition, is dead ended due to the fact that the terminal contact element or electrode I2 is disconnected from the intermediate electrode I6. Due to the impedance in this new current path, the magni- I tude of current permittedto flow is limited to a desired low value such as can be readily interrupted by a gap between the intermediate electrode I6 and main electrode Il which, at the time of interruption, is swept by gases under pressure produced by the Initial movement of the electrode I2.

In the form of the invention shown in Fig. 1 and in the same structure associated with the auxiliary circuit, there is, on initiation of the opening of the circuit, a gas pressure produced in the chamber II which, upon movement of the intermediate electrode Il out of contact with the electrode Il, passes through the gap tending to quench the arc. By use of the auxiliary circuit, the current flowing at the time of breaking the contact of the intermediate electrode I6 with the main electrode Il is reduced to a low value permitting a more ready separation and less arcing than is the case when the auxiliary circuit is not utilized. 'I'hus the auxiliary circuit is adaptable for use under differing conditions or structural form and relationship of circuit breaker parts, the structure of Fig. 1 being illustrative of a convenient means for positioning the interwhereby the magnitude o! the current ilow in the main circuit prior to interruption is reduced. Consequently the use of an auxiliary circuit will increase what may be termed the interrupting" capacity of a particular circuit breaker.

The breaker as heretofore described in (letti1l may be varied in structure particularly for the adaptation of the breaker for various characters of installation and the auxiliary circuit described for producing a potential at the intermediate electrode positioned or positionable in the arc path, may be varied in impedance, capacitance etc.,to thereby adapt the same for use with circuit breakers of diiierent current capadity.

It is obvious that various changes may be made in structure and in the auxiliary circuit without departing from the spirit and scope of the invention as set forth in the appended claims. The impedance 23 may be a separate element as shown or may 'oe incorporated in the transformer 22 and while I have shown a capacitaiiee 2l lor shunting the secondary transformer, it is not essential but appears to improve the effectiveness of the circuit. The housing ii may be of any desired construction or form and the material utilized in the contact supporting parts may be varied in respect to the gas generating and arc resisting qualities, depending upon the duty and character of the circuit with which my improved circuit breaker is usable.-

It is evident from the foregoing that my improved circuit breaker is ci! a comparatively small and compact form, materially less expen-` sive than the usual circuit breakers oi the same capacity utilizingan insulating liquid and that the various objects and features oi the invention are attained by the structures described.

Having thus fully described my invention, its

utility and mode of operation, what I claim and desire to secure by Letters Patent of the United States is- 1. A circuit breaker comprising a housing of insulating material having a chamber extending longitudinally thereof and having an opening through the housing wall to atmosphere, a pair of main contact members in the housing, one of the said contacts beinga'diacent the said opening and having a passageway therethrough, an intermediate contact positioned in the arc path between the said main contacts and normally in engagement therewith thereby closing the said passageway in the one main contact, said main contact being spring supported, means for withdrawing the other main contact from engagement with the intermediate contact thereby drawing an arc in the chamber-'and producing a high gas pressure therein, and means whereby, in withdrawal of the said other main contact, the intermediate contact is in sequence withdrawn fromk engagement with the main contact having the passageway thereby opening the chamber to atmosphere and causing a passage of the gases across the normally contacting surfaces of the intermediate contact and the said main contact having the passageway, and means for imposing a positive potential at the intermediate contact during the opening of the circuit breaker.

2. A circuit breaker comprising a housing of insulating material having a chamber, a pair of main contact elements therein forming the termirials in an electric circuit, an intermediate contact element positioned between and normally engaged by the main contact, means for withdrawing one of the main contacts from engagement with the intermediate contact thereby pro'- ducing an arc in the said chamber, the chamber being normally closed to atmosphere by the intermediate contact and the drawn arc generating a high pressure gas within the chamber, and means whereby, in the withdrawal of the said main contact, the intermediate contact is in sequence withdrawn from engagement with the other main contact and opening the chamber to atmosphere thereby permitting the passage of the high pressure gases across the contacting surfaces o! the said intermediate contact and said other main contact, and means for imposing a positive potential at the intermediate contact during the opening of the circuit breaker.

3. A circuit breaker comprising a housing formed of insulating material having a chamber therein provided with a passageway to atmosphere, a pair o! main contact elements in the chamber of the housing forming the terminale in a circuit, one of the main contacts having an aperture and being positioned at the junction of the chamber and passageway, an intermediate contact element between and normally in contact with the main contacts and closing the aperture in the apertured main contact, with- Adrawal of the other main contact from engagement with the intermediate contact producing an arc and generating high pressure within the chamber, and means whereby, on withdrawal of the said other main contact, the intermediate contact is thereby in sequence withdrawn from engagement with the apertured main contact thereby opening the chamber to atmosphere through the apertured main contact and causing the high pressure 'gases to sweep the contacting faces of the apertuned and intermediate contact elements, and means for imposing a positive potential at the intermediate contact during the opening oi the circuit breaker.

4. A circuit breaker comprising an insulating housing having a chamber therein, a ci-rcuit including a pair o! main contact elements positioned in the chamber, an intermediate contact element normally in engagement with the main contact, the chamber having a passageway to atmoephere through one of the main contacts normally closed by the intermediate contact, the arrangement providing that, on withdrawal of the other main contact from engagement with the intermediate contact, an arc is drawn and high pressure gases produced in the chamber and on withdrawal of the intermedatecontact in sequence from engagement with the first named main contact, the'arc path between the said intermediate contact and the first said main contact is swept by the high pressure gases nowing through the passageway thereby quenching the arc, and means for imposing a positive potential at the intermediate contact during the opening oi' the circuit breaker.

5. A circuit breaker comprising a housin formed of insulating material and having a chamber therein opening at one end to atmosphere, a circuit having a pair oi. main contact elements movable inthe chamber, one main contact being at the said chamber end and having an opening therethrough, the other main contact being movable in the opposite end of the chamber, a spring for said first named'main contact tending to move the same toward the other, an intermediate contact element normally engaging the first named main contact and closing the opening therethrough, means for withdrawing the second main contact from engagement with the intermediate contact thereby producing an arc and generating a high gas pressure within the chamber, said withdrawing means including a means for sequentially withdrawing the intermediate contact from engagement with the apertured main contact thereby permitting high pressure gases to sweep the contacting surfaces of the said intermediate and apertured contacts to thereby finally interrupt the circuit, and means for imposing a positive potential at the intermediate contact during the opening of the circuit breaker. Y

6. A circuit breaker having main separable contact members providing a circuit terminal, an intermediate contact therebetween normally engaged thereby, a housing formed of insulating material and having a chamber opening to atmosphere in which the several contact elements are operatively positioned, the said intermediate contact being positioned in the path of the are when the said main contact members are separated, the arrangement of the parts being such that the drawn arc upon relative separation of the main contacts produces a high pressure gas in the chamber and upon separation of the intermediate contact and the other main contact, the chamber is opened to atmosphere permitting the gases under pressure to flow between the contacting faces of the intermediate and last named contacts, and means for imposing a positive potential at the intermediate contact during the opening of the circuit breaker.

7. A circuit breaker having main separable contact members providing a circuit terminal, an intermediate contact element therebetween normally engaged thereby, a housing formed of insulating material and having a chamber, the chamber having a passageway to atmosphere normally closed by the intermediate contact when the circuit is closed through the breaker, and means for withdrawing one of the main contacts from engagement with the intermediate contact, the arrangement being such that, on separating the other contact in sequence from engagement with the intermediate contact, the arc path therebetween is swept by the high pressure gases thereby quenching the arc, and means for imposing a positive potential at the intermediate contact during the opening of the circuit breaker.

8. A circuit breaker having main separable contact members providing a circuit terminal, an intermediate contact element therebetween normally engaged thereby, a housing formed o1' insulating material and having a chamber, the chamber having a passageway to atmosphere normally closed by the intermediate contact when the circuit is closed through the breaker, and means for withdrawing one of the main contacts from engagement with the intermediate concontact, the arrangement being such that, on separating the other contact in sequence from engagement with the intermediate contact, the arc path therebetween is swept by the high pressure gases thereby quenching the arc, and an auxiliary circuit energized by the main circuit and imposing a potential at the intermediate contact positive to the surrounding arc space whereby the magnitude of current flowing in the main circuit is reduced during the opening operation i of the circuit breaker.

9. A circuit breaker having main separable contact members providing a circuit terminal, an intermediate contact element therebetween normally engaged thereby, a housing formed of insulating material and having a chamber, the chamber having a passageway to atmosphere normally closed by the intermediate contact when the circuit is closed through the breaker, and means for withdrawing one of the main contacts from engagement with the intermediate contact, the arrangement being such that, on separating the other contact in sequence from engagement with the intermediate contact, the arc path therebetween is swept by the high pressure gases thereby quenching the arc, and an auxiliary circuit electrically connecting the intermediate contact member to the main circuit and including the secondary winding of a current transformer, the primary of which is connected in the main circuit whereby during the opening oi' the circuit breaker a potential is imposed at the intermediate contact positive to the surrounding arc space and the magnitude of current flowing in the main circuit is reduced.

10. A circuit breaker having main separable contact members providing a circuit terminal, an intermediate contact element therebetween normally engaged thereby, a housing formed of insulating material and having a chamber, the chamber having a passageway to atmosphere normally closed by the intermediate contact when the circuit is closed through the breaker, and means for withdrawing one of the main contacts from engagement with the intermediate contact, the arrangement being such that, .m separating the other contact in sequence from engagement with the intermediate contact, the arc path therebetween is swept by the high pressure gases thereby quenching the are, and an auxiliary circuit energized by the main circuit and imposing a potential at the intermediate contact positive to the surrounding arc space whereby the magnitude of current flowing in the main circuit is reduced at the time the intermediate contact is separated from the last named main contact, said auxiliary circuit electrically connecting the intermediate contact member in the main circuit and including the secondary of a current transformer, the primary of which is connected in the main circuit, and a capacitance shunting the said secondary winding oi' tha transformer.

11. In a circuit breaker, a chambered housing, a circuit having main separable contact members in the chamber, an intermediate contact axially disposed therebetween and normally in engagement therewith, means for separating the intermediate and main contact members in such manner that during interruption of the main circuit, the intermediate contact member provides an intermediate are terminal between the main contact members, the arrangement providing that, during actuation of the contact members in interrupting the circuit, gas is first generated in the chamber and then passes to atmosphere between the intermediate contact element and one of the main contacts when separated, and an auxiliary circuit electrically connecting the intermediate contact member to the main circuit to `thereby impose a positive potential upon the intermediate contact during separation of the contacts and reducing the intensity of the arc to be quenched by the flow of gases from the chamber.

12. An electric circuit breaker comprising a housing of insulating material having a chamber, a cir-cuit having main separable contacts providing terminals and an intermediate contact axially disposed therebetween, said contact members being disposed in the chamber and the chamber having an opening to` atmosphere closed by the intermediate contact, means for moving the intermediate contact and opening the chamber to the passage of gases therefrom, said means for moving the intermediate contact member being of such character that, during interruption of the circuit, the intermediate contact forms an intermediate arc terminal between the said main Contact members, an auxiliary circuit electrically connected with the intermediate contact member and the main circuit, and an impedance in the auxiliary circuit for limiting the magnitude of current iiow in the main circuit, said auxiliary circuit providing means for imposing a potential upon the intermediate contact member during separation of the main contacts that is substantially positive to the surrounding arc space thereby diverting and reducing the magnitude of the subsequent current flow in the main circuit and facilitating interruption thereof.

13. A circuit breaker comprising an insulating housing having a chamber and a main circuit including a pair of contact members positioned in the chamber, an intermediate contact member normally in engagement with the main contacts, the chamber having a passageway to atmosphere and one of the main contacts having an opening leading thereto closed by the intermediate Contact when the circuit is closed through the breaker, an auxiliary circuit having a source adapted to impose a potential uponthe intermediate contact substantially positive to the arc space surrounding the same whereby, when separated from the other main contact and the passageway opened, the magnitude of current flowing in the main circuit is reduced, and the gases generated in the chamber pass between the intermediate contact and the last named main contact to the passageway.

I4. A circuit breaker comprising an insulating housing having a chamber therein, a main circuit including a pair of main contact members positioned in the chamber, an intermediate contact member normally in contact with the main contacts, the chamber having a passageway to atmosphere normally closed by the intermediate contact when the circuit is closed through the breaker, an auxiliarycircuit energized by the main circuit to impose a potential upon the intermediate contact substantially positive to the arc space immediately surrounding the same whereby, when separated from the other main contact and the passageway opened, the magnitude of vcurrent owing in the main circuit is reduced, and the gases generated in the chamber pass between the intermediate contact and the last named main contact to the passageway.

15. In an electrical circuit breaker, a pair of main separable contact members forming the terminals of the circuit to be interrupted, an additional contact member, means supporting the said additional contact member in the arc path between the said main separable contact members, and an auxiliary circuit electrically connecting the additional contact member to the main circuit, the said auxiliary circuit including a source imposing a potential upon the said additional contact during separation of the main i Contact members that is positive to the space surrounding the said additional Contact member.

16. In an electrical circuit breaker for interruption of a circuit, a pair of main separable contact members forming the terminals oi the circuit to be interrupted, an additional Contact member, insulating means supporting the said additional contact member axially between the said main contact members, an auxiliary circuit electrically connecting the additional contact member to the maincircuit, an impedance in the auxiliary circuit, anda transformer, the secondary winding thereof being in the auxiliary circuit and the primary of which is energized from the main circuit whereby during the opening of the main circuit a positive potential is imposed on the additional electrode and current flowing in the circuit being interrupted is diverted and reduced in magnitude thereby facilitating interruption,

17. In an electrical circuit breaker for interruption of a circuit, a pair of main separable contact members forming the terminals of the circuit to be interrupted, an additional contact member, insulating means supporting the said additional contact member axially between the said main contact members, an auxiliary circuit electrically connecting the additional contact member to the main circuit, an impedance in the auxiliary circuit, a transformer, the secondary winding thereof being in the auxiliary circuit and the primary winding being energized from the main circuit, and a capacitance shunting the said secondary winding whereby during opening of the main cirv cuit current iiow is diverted and reduced in magnitude thereby facilitating interruption thereof.

18. In an electrical circuit breaker, a pair of axially aligned main contact elements forming the terminals of a circuit to be interrupted, an intermediate member, means positioning the intermediate member axially and in the arc path between the main contact members, and an auxiliarycircuit electrically connecting the intermediate member to the main circuit, said auxiliary circuit including an impedance, and the `seconda-ry winding of a current transformer, the

primary winding of which is connected in the main circuit.

19. In an electrical circuit breaker having main contact elements forming terminals of a circuit to be interrupted, an intermediate member positioned in the arc path between' said contact elements, and an auxiliary circuit electrically connecting the intermediate member to the main circuit, the auxiliary circuit including a source imposing a potional on the intermediate member substantially positive to the space surrounding the same.

20. In an electrical circuit breaker having separable contact members, an auxiliary circuit connecting.one of the Contact members to a point in the path of an arc drawn therebetween, said auxiliaryc'ircuit including a source for impressing a potential substantially positive tothe are space at the said point in the arc path.

'oLAv MASENG. 

